Despite the introduction of computer aided-design and manufacturing software systems into the hearing aid industry, there continue to be legacy business practices, particularly with respect to the design and manufacture of the physical hearing aid shell itself. These practices include sending a physical impression mold of a patient's ear by mail to a manufacturing site where a hearing aid shell will be produced. Furthermore, dispensers (i.e., hearing aid professionals who advise patients and recommend hearing instruments) select a shell model, electronic instrumentation and optional components on the device without any prior knowledge as to whether the preferred selection can be physically assembled into the resulting shell. With these limitations, the dispenser is repeatedly contacted during the design of the instrument when physical shell size limitations arise. This leads to long turnaround time for creating a patient's hearing aid instruments.